This invention relates to a device for making and breaking circuits in automotive switch assemblies where the switch operation involves actuation by a foot pedal which moves a cam to impart motion to a contact which opens or closes an electrical circuit. Automotive brake pedal actuated switch assemblies are widely used to control a variety of automotive functions when a brake pedal is depressed such as: energizing brake lights, deactivating a cruise control, signaling an anti-lock brake system, signaling a torque converter clutch, and signaling a brake/transmission shift interlock.
While many automobile functions depend upon the use of brake pedal actuated switches, most pedal switch assemblies contain only a few switches. Because of this, many automobiles require more than one switch assembly to perform all of the necessary brake related functions. Automobiles with more than two or three brake related applications generally require two or more switch assemblies. Furthermore, some automobiles provide more than one switch assembly to supply a redundant switch in case one of the switch assemblies becomes jammed or is inoperative for some reason. In this case, the second switch assembly will relay the necessary signal to the particular brake related function when the first switch assembly fails. This redundancy is especially desirable with safety features such as a cruise control release which deactivates an automobile's cruise control upon depression of the brake pedal.
While two or more switch assemblies may relieve the concerns for redundancy and an ample number of switches, numerous switching assemblies create problems in s terms of spatial concerns, extra vehical weight, increased costs of labor, and increased costs of material. Spatial concerns arise when more than one pedal switch assembly must contact the brake pedal because there is often a problem in finding a way to fit the housings against the brake pedal. Vehical weight increases with the extra switch assemblies and their mounting means, and this is a concern to automobile manufacturers. Material costs for the extra assemblies and their necessary wiring place an additional burden on total vehical cost. Also, extra installation time causes labor costs to increase with each extra assembly.
In modern automobiles, electronic controls are becoming more prevalent. For this reason there is a need to generate a signal from the brake pedal that is related to the distance of pedal movement. This analog signal can then be transferred to an on-board computer to control braking functions depending upon the magnitude of the signal that is received from the brake pedal. Most of today's pedal switch assemblies only use simple single pole, single throw switches to turn braking devises on or off depending upon whether the pedal has been engaged to a certain extent. Because these switch assemblies are mainly limited to single pole single throw switches, their usefulness on modern automobiles with on board computers is limited. Versatile switch assemblies are needed today because some automobiles are moving toward braking systems that are mainly controlled by electronics, while other automobiles continue to use braking systems that are more mechanically controlled.
Another problem in pedal switch technology is that arcing during contact making and breaking in high voltage switching circuits can cause arcing noise which interferes with the automobile's audio system. To minimize the interference, a capacitor is sometimes used in the circuit to filter the effects of any electrical signal that is generated by arcing across contacts. In some previous applications, a capacitor has been connected in parallel to terminals which mate with the terminals of the brake switch assembly. In such an arrangement, the capacitor is connected to the pedal switch entirely aside from the switching assembly. The addition of a capacitor outside of the switching assembly causes increased costs by way of labor, time, and connection materials. To reduce these costs, there is a need for a capacitor that acts as an electrical filtering capacitor and is connected to the pedal switch assembly itself. This would mean that once the pedal switch assembly is installed, other installation steps would not be required to place a filtering capacitor on the pedal switch.